Hi Ryan,
I am not super familiar with Black Walnut, but most of the trees around here that are known for alleopathic properties seem to be way overblown. The highest concentrations of juglone are almost always in the buds, flowers, leaves, and
roots. These are the least likely to be chipped up, and most likely the smallest percentage of material in the pile. I have used straight cedar chips (including leaves) around fruit trees and in my gardens. While cedar is not as bad as Black Walnut, I have never had the slightest bit of problem.
It might not hurt to leave the pile for 6 months to marinate a little and start getting some good fungi growing in it... but that has nothing to do with it being alleopathic. If you wanted to be extra careful, you could just use it on paths instead of right next to plants you are growing.
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